AIDS Vaccine Trial Showed Signs of Promise
Researchers Remained Cautious About Thailand Success
Sep 24, 2009
After more than 25 years of failed efforts to perfect a vaccine for HIV/AIDS, the news out of Thailand on September 24, 2009 had scientists and researchers, for the very first time, expressing measured degrees of optimism following the positive results of the latest clinical vaccine trial.
Official announcements proclaimed that the trial vaccine had reduced the risk of HIV infection by more than 31 percent. Yet, despite these numbers, the Thailand trial was not categorized as a complete success.
However, for many, the discovery of an experimental AIDS vaccine that proved effective in preventing the spread of infection, by even a small margin, was hailed as a promising result. This was news that would lay the groundwork for more clinical studies, more research into a cure, and more hope for an end to the deadly disease.
Thai Phase III HIV Study
According to a National Institute of Allergy and Infectious Diseases (NIAID) press release, the Thai Phase III HIV vaccine study (RV144) was initiated in 2003 and marked the largest clinical test of its kind to date. With support from multiple agencies which included the United States Department of Defense, the Thai Ministry of Public Health, U.S. National Institutes of Health (NIH), and NIAID, the trial involved more than 16,000 volunteers from provinces in Thailand known to have the highest rates of HIV infection in that country.
All vaccinations were completed by July 2006 with all volunteers receiving counseling and HIV testing every six months over the course of the next three years. Some individuals were given the actual vaccine, while others were given placebos.
Reduced HIV Infections
Results of the clinical trial revealed that only 74 people out of 8,198 placebo recipients became infected with HIV, compared to 51 of the 8,197 volunteers who received the vaccine. This level of effectiveness in preventing HIV infection was found to be statistically significant. Scientists considered a 1/3 reduction in HIV infection, with a vaccine trial, to be hopeful at the very least.
Researchers determined that it was a combination of the ALVAC vaccine, made by Paris- based Sanofi-Aventis SA, and AIDSVAX, from VaxGen, that safely cut infections by 31.2 percent. Scientists were still investigating why the combination was effective, when neither vaccine showed capability of stopping the spread of HIV when used separately.
Information from this trial would likely be used in future studies to aid scientists in designing all subsequent HIV vaccines. Many researchers, wanting to remain cautious, stated it was simply too early to be overjoyed by the results and that a vaccine that can be distributed to the general population was still a very long way off.
Worldwide AIDS Pandemic
Since HIV/AIDS first appeared in the early 1980s, medical and scientific communities have been unable to come up with a vaccine for the virus. The pandemic that is Acquired Immunodeficiency Syndrome (AIDS) continues to infect roughly 6,800 new people every day on a global scale. According to the latest statistics, 32.1 million people have HIV worldwide, and more than 2 million die each year from AIDS.
While there are treatments for HIV that can control and limit the virus, keeping the virus from developing into full-blown AIDS, there is no cure as yet. Hopefully, clinical trials, such as RV144, may soon change this fact.
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